Human endogenous retrovirus-K (HERV-K) reverse transcriptase (RT) structure and biochemistry reveals remarkable similarities to HIV-1 RT and opportunities for HERV-K-specific inhibition.

Human endogenous retroviruses (HERVs) comprise nearly 8% of the human genome and are derived from ancient integrations of retroviruses into the germline. The biology of HERVs is poorly defined, but there is accumulating evidence supporting pathological roles in diverse diseases, such as cancer, autoimmune, and neurodegenerative diseases. Functional proteins are produced by HERV-encoded genes, including reverse transcriptases (RTs), which could be a contributor to the pathology attributed to aberrant HERV-K expression. To facilitate the discovery and development of HERV-K RT potent and selective inhibitors, we expressed active HERV-K RT and determined the crystal structure of a ternary complex of this enzyme with a double-stranded DNA substrate. We demonstrate a range of RT inhibition with antiretroviral nucleotide analogs, while classic nonnucleoside analogs do not inhibit HERV-K RT. Detailed comparisons of HERV-K RT with other known RTs demonstrate similarities to diverse RT families and a striking similarity to the HIV-1 RT asymmetric heterodimer. Our analysis further reveals opportunities for selective HERV-K RT inhibition.

Distinct profile of antiviral drugs effects in aortic and pulmonary endothelial cells revealed by high-content microscopy and cell painting assays.

Antiretroviral therapy have significantly improved the treatment of viral infections and reduced the associated mortality and morbidity rates. However, highly effective antiretroviral therapy (HAART) may lead to an increased risk of cardiovascular diseases, which could be related to endothelial toxicity. Here, seven antiviral drugs (remdesivir, PF-00835231, ritonavir, lopinavir, efavirenz, zidovudine and abacavir) were characterized against aortic (HAEC) and pulmonary (hLMVEC) endothelial cells, using high-content microscopy. The colourimetric study (MTS test) revealed similar toxicity profiles of all antiviral drugs tested in the concentration range of 1 nM-50 µM in aortic and pulmonary endothelial cells. Conversely, the drugs' effects on morphological parameters were more pronounced in HAECs as compared with hLMVECs. Based on the antiviral drugs' effects on the cytoplasmic and nuclei architecture (analyzed by multiple pre-defined parameters including SER texture and STAR morphology), the studied compounds were classified into five distinct morphological subgroups, each linked to a specific cellular response profile. In relation to morphological subgroup classification, antiviral drugs induced a loss of mitochondrial membrane potential, elevated ROS, changed lipid droplets/lysosomal content, decreased von Willebrand factor expression and micronuclei formation or dysregulated cellular autophagy. In conclusion, based on specific changes in endothelial cytoplasm, nuclei and subcellular morphology, the distinct endothelial response was identified for remdesivir, ritonavir, lopinavir, efavirenz, zidovudine and abacavir treatments. The effects detected in aortic endothelial cells were not detected in pulmonary endothelial cells. Taken together, high-content microscopy has proven to be a robust and informative method for endothelial drug profiling that may prove useful in predicting the organ-specific endothelial toxicity of various drugs.

Lamivudine, Doravirine, and Cabotegravir Downregulate the Expression of Human Endogenous Retroviruses (HERVs), Inhibit Cell Growth, and Reduce Invasive Capability in Melanoma Cell Lines.

This study explores the impact of antiretroviral administration on the expression of human endogenous retroviruses (HERVs), cell growth, and invasive capability of human melanoma cell lines in culture. We investigated three antiretrovirals-lamivudine, doravirine, and cabotegravir-in A375, FO-1, and SK-Mel-28, BRAF-mutated, and in MeWo, P53-mutated, melanoma cell lines. The findings indicate a general capability of these drugs to downregulate the expression of HERV-K Pol and Env genes and hinder cell viability, mobility, and colony formation capacity of melanoma cells. The antiretroviral drugs also demonstrate selectivity against malignant cells, sparing normal human epithelial melanocytes. The study reveals that the integrase inhibitor cabotegravir is particularly effective in inhibiting cell growth and invasion across different cell lines in comparison with lamivudine and doravirine, which are inhibitors of the viral reverse transcriptase enzyme. The investigation further delves into the molecular mechanisms underlying the observed effects, highlighting the potential induction of ferroptosis, apoptosis, and alterations in cell cycle regulatory proteins. Our findings showed cytostatic effects principally revealed in A375, and SK-Mel-28 cell lines through a downregulation of retinoblastoma protein phosphorylation and/or cyclin D1 expression. Signs of ferroptosis were detected in both A375 cells and FO-1 cells by a decrease in glutathione peroxidase 4 and ferritin expression, as well as by an increase in transferrin protein levels. Apoptosis was also detected in FO-1 and SK-Mel-28, but only with cabotegravir treatment. Moreover, we explored the expression and activity of the stimulator of interferon genes (STING) protein and its correlation with programmed death-ligand 1 (PD-L1) expression. Both the STING activity and PD-L1 expression were decreased, suggesting that the antiretroviral treatments may counteract the detrimental effects of PD-L1 expression activation through the STING/interferon pathway triggered by HERV-K. Finally, this study underscores the potential therapeutic significance of cabotegravir in melanoma treatment. The findings also raise the prospect of using antiretroviral drugs to downregulate PD-L1 expression, potentially enhancing the therapeutic responses of immune checkpoint inhibitors.

Long-acting injectable cabotegravir for PrEP: A game-changer in HIV prevention?

BACKGROUND: Long-acting injectable cabotegravir (CAB-LA) represents a new additional option for HIV prevention in people at substantial risk of HIV infection that may fill the gaps in pre-exposure prophylaxis (PrEP) uptake, adherence, and retention in users having difficulty with oral PrEP. Data from clinical trials demonstrated that CAB-LA was safe, highly effective, and well-accepted for HIV prevention. However, the occurrence of breakthrough HIV infections despite timely injections, HIV seroconversion timing and patterns, risk of selection and dissemination of resistance-associated mutations to integrase inhibitors, complexity of follow-up, logistical considerations, and its cost effectiveness compared with oral PrEP constitute significant issues for the integration of CAB-LA into clinical routine. FINDINGS: These concerns need to be addressed before moving forward with large-scale implementation programmes. Pilot and implementation projects are required in the following areas: HIV testing algorithms, patient education, clinic procedures, protocols for switching and discontinuation, efficacy and safety in populations not included in clinical trials, and demedicalization processes. The development of models to increase the uptake of, adherence to, and persistence with and after CAB-LA injections will also be of paramount importance for success. Lessons learned from these projects will increase experience, staff expertise, and organizational and training capacities to support the roll-out of this new agent as part of HIV prevention programmes. CONCLUSION: CAB-LA has not yet achieved its full potential in HIV prevention, and strong commitment from all stakeholders is required to push CAB-LA as a game-changer in HIV response.

HIV treatment strategies across Central, Eastern and Southeastern Europe: New times, old problems.

INTRODUCTION: In the last decade, substantial differences in the epidemiology of, antiretroviral therapy (ART) for, cascade of care in and support to people with HIV in vulnerable populations have been observed between countries in Western Europe, Central Europe (CE) and Eastern Europe (EE). The aim of this study was to use a survey to explore whether ART availability and therapies have evolved in CE and EE according to European guidelines. METHODS: The Euroguidelines in Central and Eastern Europe (ECEE) Network Group conducted two identical multicentre cross-sectional online surveys in 2019 and 2021 concerning the availability and use of antiretroviral drugs (boosted protease inhibitors [bPIs], integrase inhibitors [INSTIs] and nucleoside reverse transcriptase inhibitors [NRTIs]), the introduction of a rapid ART start strategy and the use of two-drug regimens (2DRs) for starting or switching ART. We also investigated barriers to the implementation of these strategies in each region. RESULTS: In total, 18 centres participated in the study: four from CE, six from EE and eight from Southeastern Europe (SEE). Between those 2 years, older PIs were less frequently used and darunavir-based regimens were the main PIs (83%); bictegravir-based and tenofovir alafenamide-based regimens were introduced in CE and SEE but not in EE. The COVID-19 pandemic did not significantly interrupt delivery of ART in most centres. Two-thirds of centres adopted a rapid ART start strategy, mainly in pregnant women and to improve linkage of care in vulnerable populations. The main obstacle to rapid ART start was that national guidelines in several countries from all three regions did not support such as strategy or required laboratory tests first; an INSTI/NRTI combination was the most commonly prescribed regimen (75%) and was exclusively prescribed in SEE. 2DRs are increasingly used for starting or switching ART (58%), and an INSTI/NRTI was the preferred regimen (75%) in all regions and exclusively prescribed in SEE, whereas the use of bPIs declined. Metabolic disorders and adverse drug reactions were the main reasons for starting a 2DR; in the second survey, HIV RNA <500 000 c/ml and high cluster of differentiation (CD)-4 count emerged as additional important reasons. CONCLUSIONS: In just 2 years and in spite of the emergence of the COVID-19 pandemic, significant achievements concerning ART availability and strategies have occurred in CE, EE and SEE that facilitate the harmonization of those strategies with the European AIDS Clinical Society guidelines. Few exceptions exist, especially in EE. Continuous effort is needed to overcome various obstacles (administrative, financial, national guideline restrictions) in some countries.

A computational overview of integrase strand transfer inhibitors (INSTIs) against emerging and evolving drug-resistant HIV-1 integrase mutants.

AIDS (Acquired immunodeficiency syndrome) is one of the chronic and potentially life-threatening epidemics across the world. Hitherto, the non-existence of definitive drugs that could completely cure the Human immunodeficiency virus (HIV) implies an urgent necessity for the discovery of novel anti-HIV agents. Since integration is the most crucial stage in retroviral replication, hindering it can inhibit overall viral transmission. The 5 FDA-approved integrase inhibitors were computationally investigated, especially owing to the rising multiple mutations against their susceptibility. This comparative study will open new possibilities to guide the rational design of novel lead compounds for antiretroviral therapies (ARTs), more specifically the structure-based design of novel Integrase strand transfer inhibitors (INSTIs) that may possess a better resistance profile than present drugs. Further, we have discussed potent anti-HIV natural compounds and their interactions as an alternative approach, recommending the urgent need to tap into the rich vein of indigenous knowledge for reverse pharmacology. Moreover, herein, we discuss existing evidence that might change in the near future.

A Systematic Review of Risk Factors and Consequences of Nyaope Usage: The Illicit Street Drug Containing HIV Antiretrovirals.

South Africa currently has the highest number of cases of HIV in the world. HIV antiretrovirals (ARVs) are publicly available across the country to address this crisis. However, a consequence of widely available ARVs has been the diversion of these drugs for recreational usage in a drug cocktail commonly known as "nyaope" or "whoonga," which poses a significant public health concern. To better understand nyaope, we conducted a systematic review investigating the risks and consequences associated with its usage. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, searches were conducted in eight different databases and screened thereafter. Articles were eligible for inclusion if they included analysis of least one nyaope user and considered either demographics, risk factors, or consequences of usage. Data extracted included study characteristics and limitations, as well as demographic factors, risk factors for usage in the general population, and consequences. Quality assessments were performed using the Joanna Briggs Institute's tools. Searches produced a total of 228 articles and, after screening, a total of 19 articles were eligible for inclusion. There was a pooled total of 807 nyaope users, all in South Africa. Major risk factors for usage were being male, unemployed, not completing secondary education, pressure from peer groups, having HIV, prior use of cannabis, and to a lesser extent, usage of other substances such as alcohol and tobacco. While young adults tend to be at high-risk, evidence indicates that adolescents are also at-risk. Consequences of usage include high rates of infection, cortical atrophy, depression, and addiction. Addiction was shown to lead to individuals stealing from friends and family to pay for the drugs. HIV-positive nyaope users were more likely to partake in risk behaviours and tended to have high viral loads. Nyaope's rise has been linked to many health and social issues. Considering that this may also disrupt HIV control efforts in South Africa, there is an urgent need to address the rise of nyaope.

Association Between the Awareness of Antiretroviral Drugs-Related Services and Drug Accessibility During the COVID-19 Pandemic Among Patients Undergoing Antiretroviral Therapy: A Cross-Sectional Study.

In a cross-sectional survey from 21 February to 6 March, 2020, we analyzed the awareness and utilization of antiretroviral drugs (ARVs)-related services among people living with HIV during the COVID-19 pandemic in Guangzhou, China. In addition, a subgroup analysis was performed among those who needed to go to hospital to access their drugs, and we explored the association between the awareness of ARVs-related services and the accessibility of ARVs. Of 375 participants, 89.9% were aware of drug-borrowing service, 90.7% were aware of drug-delivery service and 86.9% were aware of information-assistance service. Knowing about the drug-borrowing service or the information-assistance service, knowing about at least two services and knowing about all of the three services were all positively associated with ARVs accessibility. In addition, 35 (39.3%) of those who had acquired their drugs on time received them via the drug-delivery service. To some extent, the three ARVs-related services have alleviated the difficulties in accessing ARVs during the pandemic, especially the drug-delivery service.

Acceptability of a Combination Adherence Strategy to Support HIV Antiretroviral Therapy and Pre-exposure Prophylaxis Adherence During Pregnancy and Breastfeeding in Malawi.

In two parallel pilot studies, we implemented a combination adherence intervention of patient-centered counselling and adherence supporter training, tailored to support HIV treatment (i.e., antiretroviral therapy) or prevention (i.e., pre-exposure prophylaxis, or PrEP) during pregnancy and breastfeeding. Using a mixed-methods approach, we evaluated the intervention's acceptability. We investigated engagement, satisfaction, and discussion content via survey to all 151 participants assigned to the intervention arm (51 women living with HIV, 100 PrEP-eligible women without HIV). We also conducted serial in-depth interviews with a subgroup (n = 40) at enrollment, three months, and six months. In the quantitative analysis, the vast majority reported high satisfaction with intervention components and expressed desire to receive it in the future, if made available. These findings were supported in the qualitative analysis, with favorable comments about counselor engagement, intervention content and types of support received from adherence supporters. Overall, these results demonstrate high acceptability and provide support for HIV status-neutral interventions for antiretroviral adherence.

Evaluating the "wrong-way-round" electrospray ionization of antiretroviral drugs for improved detection sensitivity.

The presence of antiretroviral drugs (ARVDs) in the aquatic environment poses a significant health risk to the ecosystem. The dilution of these compounds during wastewater treatment processes, followed by discharge into the environment, results in extremely low concentrations in the range of ng/L. Therefore, to enable detection of these low concentrations, it is important to determine the most efficient electrospray ionization (ESI) mode using the right mobile phase modifier and to establish a selective extraction procedure. In this study, we compared the ESI intensity in the positive and negative mode using both formic acid (FA) and ammonium hydroxide (NH4OH) as mobile phase modifiers. The results revealed a phenomenon known as the "wrong-way-round" (WWR) ESI in which high intensity [M + H]+ ions were detected under basic conditions using NH4OH as modifier and, similarly, high intensity [M-H]- ions were detected under acidic conditions using FA as modifier. Furthermore, mixed-mode strong cation (MCX) and mixed-mode strong anion (MAX) exchange sorbents were evaluated for extraction recoveries, which yielded extraction recoveries between 60 and 100%. Finally, the recoveries obtained using mixed-mode ion exchange sorbents compared to ion production during the ESI process provide evidence that ions produced in solution do not necessarily reflect the ions that are produced during the ESI process. Based on the results of this study, it is recommended to evaluate the optimal ionization mode under basic and acidic conditions, instead of defaulting to the use of acidic modifiers with positive ion detection.

The Role of Cyclodextrins in COVID-19 Therapy-A Literature Review.

Coronavirus disease-19 (COVID-19) emerged in December 2019 and quickly spread, giving rise to a pandemic crisis. Therefore, it triggered tireless efforts to identify the mechanisms of the disease, how to prevent and treat it, and to limit and hamper its global dissemination. Considering the above, the search for prophylactic approaches has led to a revolution in the reglementary pharmaceutical pipeline, with the approval of vaccines against COVID-19 in an unprecedented way. Moreover, a drug repurposing scheme using regulatory-approved antiretroviral agents is also being pursued. However, their physicochemical characteristics or reported adverse events have sometimes limited their use. Hence, nanotechnology has been employed to potentially overcome some of these challenges, particularly cyclodextrins. Cyclodextrins are cyclic oligosaccharides that present hydrophobic cavities suitable for complexing several drugs. This review, besides presenting studies on the inclusion of antiviral drugs in cyclodextrins, aims to summarize some currently available prophylactic and therapeutic schemes against COVID-19, highlighting those that already make use of cyclodextrins for their complexation. In addition, some new therapeutic approaches are underscored, and the potential application of cyclodextrins to increase their promising application against COVID-19 will be addressed. This review describes the instances in which the use of cyclodextrins promotes increased bioavailability, antiviral action, and the solubility of the drugs under analysis. The potential use of cyclodextrins as an active ingredient is also covered. Finally, toxicity and regulatory issues as well as future perspectives regarding the use of cyclodextrins in COVID-19 therapy will be provided.

Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds.

Currently, it is estimated that 1-2 million people worldwide are infected with HIV-2, accounting for 3-5% of the global burden of HIV. The course of HIV-2 infection is longer compared to HIV-1 infection, but without effective antiretroviral therapy (ART), a substantial proportion of infected patients will progress to AIDS and die. Antiretroviral drugs in clinical use were designed for HIV-1 and, unfortunately, some do not work as well, or do not work at all, for HIV-2. This is the case for non-nucleoside reverse transcriptase inhibitors (NNRTIs), the fusion inhibitor enfuvirtide (T-20), most protease inhibitors (PIs), the attachment inhibitor fostemsavir and most broadly neutralizing antibodies. Integrase inhibitors work well against HIV-2 and are included in first-line therapeutic regimens for HIV-2-infected patients. However, rapid emergence of drug resistance and cross-resistance within each drug class dramatically reduces second-line treatment options. New drugs are needed to treat infection with drug-resistant isolates. Here, we review the therapeutic armamentarium available to treat HIV-2-infected patients, as well as promising drugs in development. We also review HIV-2 drug resistance mutations and resistance pathways that develop in HIV-2-infected patients under treatment.

Cell-to-cell transmission of HIV-1 from provirus-activated cells to resting naïve and memory human primary CD4 T cells is highly efficient and requires CD4 and F-actin but not chemokine receptors.

Latently infected cells harboring replication-competent proviruses represent a major barrier to HIV-1 cure. One major effort to purge these cells has focused on developing the "shock and kill" approach for forcing provirus reactivation to induce cell killing by viral cytopathic effects, host immune responses, or both. We conducted kinetic and mechanistic studies of HIV-1 protein expression, virion production, and cell-to-cell virus transmission during provirus reactivation. Provirus-activated ACH-2 cells stimulated with romidepsin (RMD) or PMA produced Nef early, and then Env and Gag in parallel with the appearance of virions. Env on the surface of provirus-activated cells and cellular F-actin were critical in the formation of virological synapses to mediate cell-to-cell transmission of HIV-1 from provirus-activated cells to uninfected cells. This HIV-1 cell-to-cell transmission was substantially more efficient than transmission seen via cell-free virus spread and required F-actin remodeling and CD4, but not chemokine receptors. Resting human primary CD4+ T cells including naïve and memory subpopulations and, especially the memory CD4+ T cells, were highly susceptible to HIV-1 infection via cell-to-cell transmission. Cell-to-cell transmission of HIV-1 from provirus-activated cells was profoundly decreased by protease inhibitors (PIs) and neutralizing antibodies (nAbs) that recognize the CD4-binding site (CD4bs) such as VRC01, but not by reverse transcriptase (RT) inhibitor Emtricitabine (FTC). Therefore, our results suggest that PIs with potent blocking abilities should be used in clinical application of the "shock and kill" approach, most likely in combination with CD4bs nAbs, to prevent new HIV-1 infections.

In utero exposure to antiretroviral drugs and pregnancy outcomes: Analysis of the French ANRS pharmacovigilance database.

AIMS: In 2018, 1.07 million pregnant women received antiretroviral drugs, raising whether this affects pregnancy outcomes. We assessed the adverse pregnancy outcomes associated with prenatal antiretroviral drug exposure, notified to the French ANRS pharmacovigilance system. METHODS: An exhaustive case report series has been performed using the ANRS pharmacovigilance database. All ANRS-sponsored HIV clinical research studies using antiretroviral drugs either in pregnant women or women of childbearing age were eligible from 2004 to 2019. We analysed the following pregnancy outcomes: abortion, ectopic pregnancy, stillbirth, prematurity (<37 weeks of gestational age), low birth weight (<2500 g) and congenital abnormalities. A logistic regression was performed to assess the odds ratio (OR) for each outcome separately (if occurrence >50) compared to the outcome observed when exposed to non-nucleoside-reverse-transcriptase-inhibitor (NNRTI)-based regimen as the reference. RESULTS: Among the 34 studies selected, 918 deliveries occurred, of whom 88% had pregnancy outcomes documented. Pregnant women were mainly exposed to PI (n = 387, 48.6%), NNRTI (n = 331, 41.5%) and INI-based combinations (n = 40, 5.0%, 18 on dolutegravir). Compared to NNRTI-based combinations, there was no significant association observed with exposure to other antiretroviral combination for spontaneous abortion, prematurity or low birth weight, except an increased risk of low birth weight in new-born exposed to exclusive nucleoside-reverse-transcriptase-inhibitor (NRTI) combinations (n = 4; OR 7.50 [1.49-37.83]). CONCLUSIONS: Our study, mainly based on protease inhibitor (PI) and NNRTI-based regimens, is overall reassuring on the risk of adverse pregnancy outcomes, except for NRTI which should be interpreted cautiously (small number, indication bias). In this study, the number of integrase inhibitor (INI)-based combinations was too low to draw any conclusions.

In Vitro Susceptibility of HIV Isolates with High Growth Capability to Antiretroviral Drugs.

It has been considered that reduced susceptibility to antiretroviral drugs is influenced by drug adherence, drug tolerance and drug-resistance-related mutations in the HIV genome. In the present study, we assessed the intrinsic high viral growth capability as a potential viral factor that may influence their susceptibility to antiretroviral drugs using an in vitro model. Phytohemagglutinin-activated peripheral blood mononuclear cells (1.5 × 106 cells) were infected with HIV isolates (106 copies/mL). The culture was carried out at different concentrations (0.001-20 µM) of 13 synthetic antiretroviral compounds (six nucleoside/nucleotide reverse transcriptase inhibitors, one non-nucleoside reverse transcriptase inhibitor, four integrase inhibitors, and two protease inhibitors), and HIV production was assessed using HIV-RNA copies in culture. The 90% inhibitory concentration (IC90) and pharmacokinetics of an antiretroviral agent were used as parameters to determine the reduced antiretroviral drug susceptibility of HIV isolates with high growth capability to synthetic antiretroviral compounds. The high growth capability of HIV isolates without any known drug resistance-related mutation affected their susceptibility to tenofovir (IC90 = 2.05 ± 0.40 µM), lamivudine (IC90 = 6.83 ± 3.96 µM), emtricitabine (IC90 = 0.68 ± 0.37 µM), and efavirenz (IC90 = 3.65 ± 0.77 µM). These antiretroviral drugs showed IC90 values close to or above the maximum plasma concentration against HIV isolates with high growth capability without any known drug resistance-related mutation. Our results may contribute to the development of effective strategies to tailor and individualize antiretroviral therapy in patients harboring HIV isolates with high growth capability.

HIV-Tat Exacerbates the Actions of Atazanavir, Efavirenz, and Ritonavir on Cardiac Ryanodine Receptor (RyR2).

The incidence of sudden cardiac death (SCD) in people living with HIV infection (PLWH), especially those with inadequate viral suppression, is high and the reasons for this remain incompletely characterized. The timely opening and closing of type 2 ryanodine receptor (RyR2) is critical for ensuring rhythmic cardiac contraction-relaxation cycles, and the disruption of these processes can elicit Ca2+ waves, ventricular arrhythmias, and SCD. Herein, we show that the HIV protein Tat (HIV-Tat: 0-52 ng/mL) and therapeutic levels of the antiretroviral drugs atazanavir (ATV: 0-25,344 ng/mL), efavirenz (EFV: 0-11,376 ng/mL), and ritonavir (RTV: 0-25,956 ng/mL) bind to and modulate the opening and closing of RyR2. Abacavir (0-14,315 ng/mL), bictegravir (0-22,469 ng/mL), Rilpivirine (0-14,360 ng/mL), and tenofovir disoproxil fumarate (0-18,321 ng/mL) did not alter [3H]ryanodine binding to RyR2. Pretreating RyR2 with low HIV-Tat (14 ng/mL) potentiated the abilities of ATV and RTV to bind to open RyR2 and enhanced their ability to bind to EFV to close RyR2. In silico molecular docking using a Schrodinger Prime protein-protein docking algorithm identified three thermodynamically favored interacting sites for HIV-Tat on RyR2. The most favored site resides between amino acids (AA) 1702-1963; the second favored site resides between AA 467-1465, and the third site resides between AA 201-1816. Collectively, these new data show that HIV-Tat, ATV, EFV, and RTV can bind to and modulate the activity of RyR2 and that HIV-Tat can exacerbate the actions of ATV, EFV, and RTV on RyR2. Whether the modulation of RyR2 by these agents increases the risk of arrhythmias and SCD remains to be explored.

Fabrication of PEGylated Chitosan Nanoparticles Containing Tenofovir Alafenamide: Synthesis and Characterization.

Tenofovir alafenamide (TAF) is an antiretroviral (ARV) drug that is used for the management and prevention of human immunodeficiency virus (HIV). The clinical availability of ARV delivery systems that provide long-lasting protection against HIV transmission is lacking. There is a dire need to formulate nanocarrier systems that can help in revolutionizing the way to fight against HIV/AIDS. Here, we aimed to synthesize a polymer using chitosan and polyethylene glycol (PEG) by the PEGylation of chitosan at the hydroxyl group. After successful modification and confirmation by FTIR, XRD, and SEM, TAF-loaded PEGylated chitosan nanoparticles were prepared and analyzed for their particle size, zeta potential, morphology, crystallinity, chemical interactions, entrapment efficacy, drug loading, in vitro drug release, and release kinetic modeling. The fabricated nanoparticles were found to be in a nanosized range (219.6 nm), with ~90% entrapment efficacy, ~14% drug loading, and a spherical uniform distribution. The FTIR analysis confirmed the successful synthesis of PEGylated chitosan and nanoparticles. The in vitro analysis showed ~60% of the drug was released from the PEGylated polymeric reservoir system within 48 h at pH 7.4. The drug release kinetics were depicted by the Korsmeyer-Peppas release model with thermodynamically nonspontaneous drug release. Conclusively, PEGylated chitosan has the potential to deliver TAF from a nanocarrier system, and in the future, cytotoxicity and in vivo studies can be performed to further authenticate the synthesized polymer.

Safety and Efficacy of Starting Antiretroviral Therapy in the First Week of Life.

BACKGROUND: Early antiretroviral therapy (ART) is recommended for infants with human immunodeficiency virus (HIV) infection. However, few antiretroviral options are available for neonates. METHODS: The Early Infant Treatment Study in Botswana tested HIV-exposed infants within 96 hours of birth, and HIV-infected infants started nevirapine (NVP) 6 mg/kg twice daily, zidovudine (ZDV), and lamivudine (3TC) at age < 7 days. NVP trough concentrations were tested at 1 and 2 weeks. NVP was switched to ritonavir-boosted lopinavir (LPV/r) at week 2, 3, 4, or 5 according to delivery gestational age. RESULTS: Forty HIV-infected infants started ART at median age 2 days (range, 1-5 days). NVP trough concentrations were highly variable and below therapeutic target (3000 ng/mL) for 50% of 2-week measurements; concentrations did not correlate with viral decline at weeks 2, 4, or 12. Two deaths unrelated to ART occurred through 24 weeks. Only 1 unscheduled treatment modification was required. Within 4 weeks of transition to LPV/r, 9 (22.5%) had transient HIV RNA increases, likely due to poor LPV/r palatability. At 12 weeks, 22 (55%) of 40 were <40 copies/mL (93% <400 copies/mL); by 24 weeks, 27 of 38 (71%) were < 40 copies/mL (84% < 400 copies/mL). HIV-1 RNA response at 12 and 24 weeks did not differ by baseline HIV RNA or other factors. CONCLUSIONS: NVP/ZDV/3TC started in the first week of life was safe and effective, even when trough NVP levels were below target. Transient viral increases occurred following transition to LPV/r, but by 12 and 24 weeks most children achieved and maintained viral suppression. CLINICAL TRIALS REGISTRATION: NCT02369406.

Long-Acting HIV Drugs for Treatment and Prevention.

Antiretroviral drugs have revolutionized the treatment and prevention of HIV infection; however, adherence is critical for sustained efficacy. Current HIV treatment consists of three-drug regimens, and current HIV pre-exposure prophylaxis (PrEP) consists of a two-drug regimen; both generally require adherence to once-daily dosing. Long-acting formulations are useful in the treatment and prevention of other conditions (e.g., contraceptives, antipsychotics) and help promote adherence. Newer long-acting formulations of approved and investigational antiretroviral drugs in existing and newer mechanistic classes are under study for HIV treatment and prevention, including some phase III trials. Although long-acting antiretroviral drugs hold promise, some clinical challenges exist, including managing side effects, drug-drug interactions, pregnancy, and long-lasting drug concentrations that could lead to the development of drug resistance. This review aims to summarize currently available information on long-acting antiretroviral drugs for HIV treatment and prevention.

Effects of combination antiretroviral drugs (cART) on hippocampal neuroplasticity in female mice.

The incidence of HIV-associated neurocognitive disorder (HAND) continues despite the introduction of combination antiretroviral drugs (cART). Several studies have reported the neurotoxicity of individual antiretroviral drugs (monotherapy), while the common approach for HIV treatment is through cART. Hence, the current study investigated the effects of long-term exposure to cART on cognitive function, oxidative damage, autophagy, and neuroplasticity in the hippocampus of mice. Female Balb/c mice received a once-a-day oral dose of cART composed of emtricitabine + tenofovir disoproxil fumarate or vehicle for 8 weeks. On week 7 of drug administration, all mice were assessed for spatial learning in the Morris water maze (MWM), and then on week 8, mice were sacrificed, and hippocampal tissue dissected from the brain. For biochemical analyses, we measured the concentration of 4-hydroxynonenal, and the expression of autophagic marker LC3B, synaptophysin, and brain-derived neurotrophic factor (BDNF) in the hippocampus. Our results showed that cART exposure increased escape latency in the MWM test. The cART-treated mice also showed increased 4-hydroxynonenal concentration and expression of LC3B. Furthermore, cART treatment decreased the expression of synaptophysin and BDNF. These findings further support the evidence that cART may be neurotoxic and therefore may play a role in the neuropathogenesis of HAND.